mirror of
https://github.com/go-gitea/gitea.git
synced 2024-12-05 09:03:48 +08:00
502 lines
12 KiB
Go
502 lines
12 KiB
Go
|
// Copyright 2010 The Go Authors. All rights reserved.
|
||
|
// Use of this source code is governed by a BSD-style
|
||
|
// license that can be found in the LICENSE file.
|
||
|
|
||
|
package pgzip
|
||
|
|
||
|
import (
|
||
|
"bytes"
|
||
|
"errors"
|
||
|
"fmt"
|
||
|
"hash"
|
||
|
"hash/crc32"
|
||
|
"io"
|
||
|
"sync"
|
||
|
"time"
|
||
|
|
||
|
"github.com/klauspost/compress/flate"
|
||
|
)
|
||
|
|
||
|
const (
|
||
|
defaultBlockSize = 256 << 10
|
||
|
tailSize = 16384
|
||
|
defaultBlocks = 16
|
||
|
)
|
||
|
|
||
|
// These constants are copied from the flate package, so that code that imports
|
||
|
// "compress/gzip" does not also have to import "compress/flate".
|
||
|
const (
|
||
|
NoCompression = flate.NoCompression
|
||
|
BestSpeed = flate.BestSpeed
|
||
|
BestCompression = flate.BestCompression
|
||
|
DefaultCompression = flate.DefaultCompression
|
||
|
ConstantCompression = flate.ConstantCompression
|
||
|
HuffmanOnly = flate.HuffmanOnly
|
||
|
)
|
||
|
|
||
|
// A Writer is an io.WriteCloser.
|
||
|
// Writes to a Writer are compressed and written to w.
|
||
|
type Writer struct {
|
||
|
Header
|
||
|
w io.Writer
|
||
|
level int
|
||
|
wroteHeader bool
|
||
|
blockSize int
|
||
|
blocks int
|
||
|
currentBuffer []byte
|
||
|
prevTail []byte
|
||
|
digest hash.Hash32
|
||
|
size int
|
||
|
closed bool
|
||
|
buf [10]byte
|
||
|
errMu sync.RWMutex
|
||
|
err error
|
||
|
pushedErr chan struct{}
|
||
|
results chan result
|
||
|
dictFlatePool sync.Pool
|
||
|
dstPool sync.Pool
|
||
|
wg sync.WaitGroup
|
||
|
}
|
||
|
|
||
|
type result struct {
|
||
|
result chan []byte
|
||
|
notifyWritten chan struct{}
|
||
|
}
|
||
|
|
||
|
// Use SetConcurrency to finetune the concurrency level if needed.
|
||
|
//
|
||
|
// With this you can control the approximate size of your blocks,
|
||
|
// as well as how many you want to be processing in parallel.
|
||
|
//
|
||
|
// Default values for this is SetConcurrency(250000, 16),
|
||
|
// meaning blocks are split at 250000 bytes and up to 16 blocks
|
||
|
// can be processing at once before the writer blocks.
|
||
|
func (z *Writer) SetConcurrency(blockSize, blocks int) error {
|
||
|
if blockSize <= tailSize {
|
||
|
return fmt.Errorf("gzip: block size cannot be less than or equal to %d", tailSize)
|
||
|
}
|
||
|
if blocks <= 0 {
|
||
|
return errors.New("gzip: blocks cannot be zero or less")
|
||
|
}
|
||
|
if blockSize == z.blockSize && blocks == z.blocks {
|
||
|
return nil
|
||
|
}
|
||
|
z.blockSize = blockSize
|
||
|
z.results = make(chan result, blocks)
|
||
|
z.blocks = blocks
|
||
|
z.dstPool = sync.Pool{New: func() interface{} { return make([]byte, 0, blockSize+(blockSize)>>4) }}
|
||
|
return nil
|
||
|
}
|
||
|
|
||
|
// NewWriter returns a new Writer.
|
||
|
// Writes to the returned writer are compressed and written to w.
|
||
|
//
|
||
|
// It is the caller's responsibility to call Close on the WriteCloser when done.
|
||
|
// Writes may be buffered and not flushed until Close.
|
||
|
//
|
||
|
// Callers that wish to set the fields in Writer.Header must do so before
|
||
|
// the first call to Write or Close. The Comment and Name header fields are
|
||
|
// UTF-8 strings in Go, but the underlying format requires NUL-terminated ISO
|
||
|
// 8859-1 (Latin-1). NUL or non-Latin-1 runes in those strings will lead to an
|
||
|
// error on Write.
|
||
|
func NewWriter(w io.Writer) *Writer {
|
||
|
z, _ := NewWriterLevel(w, DefaultCompression)
|
||
|
return z
|
||
|
}
|
||
|
|
||
|
// NewWriterLevel is like NewWriter but specifies the compression level instead
|
||
|
// of assuming DefaultCompression.
|
||
|
//
|
||
|
// The compression level can be DefaultCompression, NoCompression, or any
|
||
|
// integer value between BestSpeed and BestCompression inclusive. The error
|
||
|
// returned will be nil if the level is valid.
|
||
|
func NewWriterLevel(w io.Writer, level int) (*Writer, error) {
|
||
|
if level < ConstantCompression || level > BestCompression {
|
||
|
return nil, fmt.Errorf("gzip: invalid compression level: %d", level)
|
||
|
}
|
||
|
z := new(Writer)
|
||
|
z.SetConcurrency(defaultBlockSize, defaultBlocks)
|
||
|
z.init(w, level)
|
||
|
return z, nil
|
||
|
}
|
||
|
|
||
|
// This function must be used by goroutines to set an
|
||
|
// error condition, since z.err access is restricted
|
||
|
// to the callers goruotine.
|
||
|
func (z *Writer) pushError(err error) {
|
||
|
z.errMu.Lock()
|
||
|
if z.err != nil {
|
||
|
z.errMu.Unlock()
|
||
|
return
|
||
|
}
|
||
|
z.err = err
|
||
|
close(z.pushedErr)
|
||
|
z.errMu.Unlock()
|
||
|
}
|
||
|
|
||
|
func (z *Writer) init(w io.Writer, level int) {
|
||
|
z.wg.Wait()
|
||
|
digest := z.digest
|
||
|
if digest != nil {
|
||
|
digest.Reset()
|
||
|
} else {
|
||
|
digest = crc32.NewIEEE()
|
||
|
}
|
||
|
z.Header = Header{OS: 255}
|
||
|
z.w = w
|
||
|
z.level = level
|
||
|
z.digest = digest
|
||
|
z.pushedErr = make(chan struct{}, 0)
|
||
|
z.results = make(chan result, z.blocks)
|
||
|
z.err = nil
|
||
|
z.closed = false
|
||
|
z.Comment = ""
|
||
|
z.Extra = nil
|
||
|
z.ModTime = time.Time{}
|
||
|
z.wroteHeader = false
|
||
|
z.currentBuffer = nil
|
||
|
z.buf = [10]byte{}
|
||
|
z.prevTail = nil
|
||
|
z.size = 0
|
||
|
if z.dictFlatePool.New == nil {
|
||
|
z.dictFlatePool.New = func() interface{} {
|
||
|
f, _ := flate.NewWriterDict(w, level, nil)
|
||
|
return f
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// Reset discards the Writer z's state and makes it equivalent to the
|
||
|
// result of its original state from NewWriter or NewWriterLevel, but
|
||
|
// writing to w instead. This permits reusing a Writer rather than
|
||
|
// allocating a new one.
|
||
|
func (z *Writer) Reset(w io.Writer) {
|
||
|
if z.results != nil && !z.closed {
|
||
|
close(z.results)
|
||
|
}
|
||
|
z.SetConcurrency(defaultBlockSize, defaultBlocks)
|
||
|
z.init(w, z.level)
|
||
|
}
|
||
|
|
||
|
// GZIP (RFC 1952) is little-endian, unlike ZLIB (RFC 1950).
|
||
|
func put2(p []byte, v uint16) {
|
||
|
p[0] = uint8(v >> 0)
|
||
|
p[1] = uint8(v >> 8)
|
||
|
}
|
||
|
|
||
|
func put4(p []byte, v uint32) {
|
||
|
p[0] = uint8(v >> 0)
|
||
|
p[1] = uint8(v >> 8)
|
||
|
p[2] = uint8(v >> 16)
|
||
|
p[3] = uint8(v >> 24)
|
||
|
}
|
||
|
|
||
|
// writeBytes writes a length-prefixed byte slice to z.w.
|
||
|
func (z *Writer) writeBytes(b []byte) error {
|
||
|
if len(b) > 0xffff {
|
||
|
return errors.New("gzip.Write: Extra data is too large")
|
||
|
}
|
||
|
put2(z.buf[0:2], uint16(len(b)))
|
||
|
_, err := z.w.Write(z.buf[0:2])
|
||
|
if err != nil {
|
||
|
return err
|
||
|
}
|
||
|
_, err = z.w.Write(b)
|
||
|
return err
|
||
|
}
|
||
|
|
||
|
// writeString writes a UTF-8 string s in GZIP's format to z.w.
|
||
|
// GZIP (RFC 1952) specifies that strings are NUL-terminated ISO 8859-1 (Latin-1).
|
||
|
func (z *Writer) writeString(s string) (err error) {
|
||
|
// GZIP stores Latin-1 strings; error if non-Latin-1; convert if non-ASCII.
|
||
|
needconv := false
|
||
|
for _, v := range s {
|
||
|
if v == 0 || v > 0xff {
|
||
|
return errors.New("gzip.Write: non-Latin-1 header string")
|
||
|
}
|
||
|
if v > 0x7f {
|
||
|
needconv = true
|
||
|
}
|
||
|
}
|
||
|
if needconv {
|
||
|
b := make([]byte, 0, len(s))
|
||
|
for _, v := range s {
|
||
|
b = append(b, byte(v))
|
||
|
}
|
||
|
_, err = z.w.Write(b)
|
||
|
} else {
|
||
|
_, err = io.WriteString(z.w, s)
|
||
|
}
|
||
|
if err != nil {
|
||
|
return err
|
||
|
}
|
||
|
// GZIP strings are NUL-terminated.
|
||
|
z.buf[0] = 0
|
||
|
_, err = z.w.Write(z.buf[0:1])
|
||
|
return err
|
||
|
}
|
||
|
|
||
|
// compressCurrent will compress the data currently buffered
|
||
|
// This should only be called from the main writer/flush/closer
|
||
|
func (z *Writer) compressCurrent(flush bool) {
|
||
|
r := result{}
|
||
|
r.result = make(chan []byte, 1)
|
||
|
r.notifyWritten = make(chan struct{}, 0)
|
||
|
select {
|
||
|
case z.results <- r:
|
||
|
case <-z.pushedErr:
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// If block given is more than twice the block size, split it.
|
||
|
c := z.currentBuffer
|
||
|
if len(c) > z.blockSize*2 {
|
||
|
c = c[:z.blockSize]
|
||
|
z.wg.Add(1)
|
||
|
go z.compressBlock(c, z.prevTail, r, false)
|
||
|
z.prevTail = c[len(c)-tailSize:]
|
||
|
z.currentBuffer = z.currentBuffer[z.blockSize:]
|
||
|
z.compressCurrent(flush)
|
||
|
// Last one flushes if needed
|
||
|
return
|
||
|
}
|
||
|
|
||
|
z.wg.Add(1)
|
||
|
go z.compressBlock(c, z.prevTail, r, z.closed)
|
||
|
if len(c) > tailSize {
|
||
|
z.prevTail = c[len(c)-tailSize:]
|
||
|
} else {
|
||
|
z.prevTail = nil
|
||
|
}
|
||
|
z.currentBuffer = z.dstPool.Get().([]byte)
|
||
|
z.currentBuffer = z.currentBuffer[:0]
|
||
|
|
||
|
// Wait if flushing
|
||
|
if flush {
|
||
|
<-r.notifyWritten
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// Returns an error if it has been set.
|
||
|
// Cannot be used by functions that are from internal goroutines.
|
||
|
func (z *Writer) checkError() error {
|
||
|
z.errMu.RLock()
|
||
|
err := z.err
|
||
|
z.errMu.RUnlock()
|
||
|
return err
|
||
|
}
|
||
|
|
||
|
// Write writes a compressed form of p to the underlying io.Writer. The
|
||
|
// compressed bytes are not necessarily flushed to output until
|
||
|
// the Writer is closed or Flush() is called.
|
||
|
//
|
||
|
// The function will return quickly, if there are unused buffers.
|
||
|
// The sent slice (p) is copied, and the caller is free to re-use the buffer
|
||
|
// when the function returns.
|
||
|
//
|
||
|
// Errors that occur during compression will be reported later, and a nil error
|
||
|
// does not signify that the compression succeeded (since it is most likely still running)
|
||
|
// That means that the call that returns an error may not be the call that caused it.
|
||
|
// Only Flush and Close functions are guaranteed to return any errors up to that point.
|
||
|
func (z *Writer) Write(p []byte) (int, error) {
|
||
|
if err := z.checkError(); err != nil {
|
||
|
return 0, err
|
||
|
}
|
||
|
// Write the GZIP header lazily.
|
||
|
if !z.wroteHeader {
|
||
|
z.wroteHeader = true
|
||
|
z.buf[0] = gzipID1
|
||
|
z.buf[1] = gzipID2
|
||
|
z.buf[2] = gzipDeflate
|
||
|
z.buf[3] = 0
|
||
|
if z.Extra != nil {
|
||
|
z.buf[3] |= 0x04
|
||
|
}
|
||
|
if z.Name != "" {
|
||
|
z.buf[3] |= 0x08
|
||
|
}
|
||
|
if z.Comment != "" {
|
||
|
z.buf[3] |= 0x10
|
||
|
}
|
||
|
put4(z.buf[4:8], uint32(z.ModTime.Unix()))
|
||
|
if z.level == BestCompression {
|
||
|
z.buf[8] = 2
|
||
|
} else if z.level == BestSpeed {
|
||
|
z.buf[8] = 4
|
||
|
} else {
|
||
|
z.buf[8] = 0
|
||
|
}
|
||
|
z.buf[9] = z.OS
|
||
|
var n int
|
||
|
var err error
|
||
|
n, err = z.w.Write(z.buf[0:10])
|
||
|
if err != nil {
|
||
|
z.pushError(err)
|
||
|
return n, err
|
||
|
}
|
||
|
if z.Extra != nil {
|
||
|
err = z.writeBytes(z.Extra)
|
||
|
if err != nil {
|
||
|
z.pushError(err)
|
||
|
return n, err
|
||
|
}
|
||
|
}
|
||
|
if z.Name != "" {
|
||
|
err = z.writeString(z.Name)
|
||
|
if err != nil {
|
||
|
z.pushError(err)
|
||
|
return n, err
|
||
|
}
|
||
|
}
|
||
|
if z.Comment != "" {
|
||
|
err = z.writeString(z.Comment)
|
||
|
if err != nil {
|
||
|
z.pushError(err)
|
||
|
return n, err
|
||
|
}
|
||
|
}
|
||
|
// Start receiving data from compressors
|
||
|
go func() {
|
||
|
listen := z.results
|
||
|
for {
|
||
|
r, ok := <-listen
|
||
|
// If closed, we are finished.
|
||
|
if !ok {
|
||
|
return
|
||
|
}
|
||
|
buf := <-r.result
|
||
|
n, err := z.w.Write(buf)
|
||
|
if err != nil {
|
||
|
z.pushError(err)
|
||
|
close(r.notifyWritten)
|
||
|
return
|
||
|
}
|
||
|
if n != len(buf) {
|
||
|
z.pushError(fmt.Errorf("gzip: short write %d should be %d", n, len(buf)))
|
||
|
close(r.notifyWritten)
|
||
|
return
|
||
|
}
|
||
|
z.dstPool.Put(buf)
|
||
|
close(r.notifyWritten)
|
||
|
}
|
||
|
}()
|
||
|
z.currentBuffer = make([]byte, 0, z.blockSize)
|
||
|
}
|
||
|
q := p
|
||
|
for len(q) > 0 {
|
||
|
length := len(q)
|
||
|
if length+len(z.currentBuffer) > z.blockSize {
|
||
|
length = z.blockSize - len(z.currentBuffer)
|
||
|
}
|
||
|
z.digest.Write(q[:length])
|
||
|
z.currentBuffer = append(z.currentBuffer, q[:length]...)
|
||
|
if len(z.currentBuffer) >= z.blockSize {
|
||
|
z.compressCurrent(false)
|
||
|
if err := z.checkError(); err != nil {
|
||
|
return len(p) - len(q) - length, err
|
||
|
}
|
||
|
}
|
||
|
z.size += length
|
||
|
q = q[length:]
|
||
|
}
|
||
|
return len(p), z.checkError()
|
||
|
}
|
||
|
|
||
|
// Step 1: compresses buffer to buffer
|
||
|
// Step 2: send writer to channel
|
||
|
// Step 3: Close result channel to indicate we are done
|
||
|
func (z *Writer) compressBlock(p, prevTail []byte, r result, closed bool) {
|
||
|
defer func() {
|
||
|
close(r.result)
|
||
|
z.wg.Done()
|
||
|
}()
|
||
|
buf := z.dstPool.Get().([]byte)
|
||
|
dest := bytes.NewBuffer(buf[:0])
|
||
|
|
||
|
compressor := z.dictFlatePool.Get().(*flate.Writer)
|
||
|
compressor.ResetDict(dest, prevTail)
|
||
|
compressor.Write(p)
|
||
|
|
||
|
err := compressor.Flush()
|
||
|
if err != nil {
|
||
|
z.pushError(err)
|
||
|
return
|
||
|
}
|
||
|
if closed {
|
||
|
err = compressor.Close()
|
||
|
if err != nil {
|
||
|
z.pushError(err)
|
||
|
return
|
||
|
}
|
||
|
}
|
||
|
z.dictFlatePool.Put(compressor)
|
||
|
// Read back buffer
|
||
|
buf = dest.Bytes()
|
||
|
r.result <- buf
|
||
|
}
|
||
|
|
||
|
// Flush flushes any pending compressed data to the underlying writer.
|
||
|
//
|
||
|
// It is useful mainly in compressed network protocols, to ensure that
|
||
|
// a remote reader has enough data to reconstruct a packet. Flush does
|
||
|
// not return until the data has been written. If the underlying
|
||
|
// writer returns an error, Flush returns that error.
|
||
|
//
|
||
|
// In the terminology of the zlib library, Flush is equivalent to Z_SYNC_FLUSH.
|
||
|
func (z *Writer) Flush() error {
|
||
|
if err := z.checkError(); err != nil {
|
||
|
return err
|
||
|
}
|
||
|
if z.closed {
|
||
|
return nil
|
||
|
}
|
||
|
if !z.wroteHeader {
|
||
|
_, err := z.Write(nil)
|
||
|
if err != nil {
|
||
|
return err
|
||
|
}
|
||
|
}
|
||
|
// We send current block to compression
|
||
|
z.compressCurrent(true)
|
||
|
|
||
|
return z.checkError()
|
||
|
}
|
||
|
|
||
|
// UncompressedSize will return the number of bytes written.
|
||
|
// pgzip only, not a function in the official gzip package.
|
||
|
func (z *Writer) UncompressedSize() int {
|
||
|
return z.size
|
||
|
}
|
||
|
|
||
|
// Close closes the Writer, flushing any unwritten data to the underlying
|
||
|
// io.Writer, but does not close the underlying io.Writer.
|
||
|
func (z *Writer) Close() error {
|
||
|
if err := z.checkError(); err != nil {
|
||
|
return err
|
||
|
}
|
||
|
if z.closed {
|
||
|
return nil
|
||
|
}
|
||
|
|
||
|
z.closed = true
|
||
|
if !z.wroteHeader {
|
||
|
z.Write(nil)
|
||
|
if err := z.checkError(); err != nil {
|
||
|
return err
|
||
|
}
|
||
|
}
|
||
|
z.compressCurrent(true)
|
||
|
if err := z.checkError(); err != nil {
|
||
|
return err
|
||
|
}
|
||
|
close(z.results)
|
||
|
put4(z.buf[0:4], z.digest.Sum32())
|
||
|
put4(z.buf[4:8], uint32(z.size))
|
||
|
_, err := z.w.Write(z.buf[0:8])
|
||
|
if err != nil {
|
||
|
z.pushError(err)
|
||
|
return err
|
||
|
}
|
||
|
return nil
|
||
|
}
|